It seems that one of the primary sources of Methane might be from an unexpected source.
The National Geographic has the story:
Plants Exhale Methane, Contribute to Warming, Study Says
Grasses and other green growth may produce 10 to 30 percent of Earth's annual methane output, a new study reports, making plants a surprising�and potentially significant�contributor to global warming.
Until the data were unveiled in this week's Nature, scientists had believed that plant-related methane formed only in oxygen-free environments, such as bogs.
But a team of European researchers identified a large range of plants that release methane under normal growing conditions. The gas also seeps from dead plant material.
David Lowe is a study co-author and an atmospheric chemist with the National Institute of Water and Atmospheric Research in Wellington, New Zealand.
According to Lowe, "We now have the specter that new forests might increase greenhouse warming through methane emissions rather than decrease it by being sinks for carbon dioxide."
Kind of reinforces the thought that any attempt to model the climate will be wrong. Climatology is still a very very young science and we are just starting to scratch the surface.
There is also a marked tendency in the press to ignore historical data such as the 400 year periodic cycle of warming and cooling and the 40-80 year cycle of Arctic Ice advancing and receding.
Sure, the climate is changing -- it always does. To assign the concept that humans are the cause is hubris at a very large scale.
